; /+===========================================================+/ ; // // ; // Modulo-free 8bit Zoom Sprite // ; // // ;/+===========================================================+/ ; KZoomSprite.i ; ->krabob@online.fr<- (Vic Ferry) 01-02-2001 ; ; This routines support free-resolution screens+ ; free-resolution texture+ ; free rectangle clipping+ ; coordinate-exchange. ; 16 bit shifted- fixed comas UV coordinates. ; ; phxass command line to make a .o: ; phxass KZoomSprite.i I=include: M=68020 ; all macros needed to create some structures. incdir include: include exec/types.i STRUCTURE ScreenRenderContext,0 APTR src_ChunkyScreen LONG src_BytesModulo LONG src_ClipX1 LONG src_ClipY1 LONG src_ClipX2 LONG src_ClipY2 LABEL src_SIZEOF STRUCTURE TextureContext,0 APTR ttc_ChunkyTexture LONG ttc_BytesModulo LONG ttc_U1 ;<<16 LONG ttc_V1 ;<<16 LONG ttc_U2 ;<<16 LONG ttc_V2 ;<<16 LABEL ttc_SIZEOF ;Following instructions - fmul.s fp0,fp1 ; move.l d0,d2 ; move.l d1,d3 ; move.l d2,d4 ; add.l d5,d6 ; add.l d0,d1 - executes in 3 cycles !!! ; d0.l x1 Rectangle to fit on Chunky Screen. ; d1.l y1 ; d2.l x2 ; d3.l y2 ; a0.l Screen Render Context (Pointer) ; a1.l TextureContext (Pointer) XDEF KZoomSprite8bit68K XDEF _KZoomSprite8bit68K section ZoomSprite,code KZoomSprite8bit68K _KZoomSprite8bit68K movem.l d0-d7/a0-a6,-(sp) ; a2 kept for evt. table. ; +---------------------------------------------+ ; / Prepare Height vectors / ;+---------------------------------------------+ move.l d0,a4 ;X1,X2 kept move.l d2,a5 ; +-------------------------------------+ ; / Swap if order Y is not right / ;+-------------------------------------+ ;d1 Y1 ;d3 Y2 move.l ttc_V1(a1),d5 ;V1 move.l ttc_V2(a1),d6 ;V2 cmp.l d3,d1 beq .end ; exit if 0 lines blt .noswapY ; if Y1>Y2 swap values move.l d1,d7 move.l d3,d1 move.l d7,d3 move.l d5,d7 move.l d6,d5 move.l d7,d6 sub.l #65536,d5 ;last pixel ->first is out (sub logic) sub.l #65536,d6 .noswapY ; Here: ; d0: - ; d1: Y1 ; d2: - ; d3: Y2 ; d4: - ; d5: V1 ; d6: V2 ; d7: -usually calculation- ; a0: RC ; a1: TXTC ; a2: kept for table ; a3: (will be chunky ptr) ; a4: X1 ; a5: X2 ; +-------------------------------------+ ; / Clip Up / ;+-------------------------------------+ move.l src_ClipY1(a0),d4 cmp.l d4,d3 ble .end ;if out up, exit cmp.l d1,d4 ; have to be clipped or not ? ble .noclip_up ; >0 had to be clipped ;d5= V1 = ... ; a=(d4-d1) (>0) ; b=(d3-d1) (>0) ;Ub=(d6-d5) ;Ua=(Ub/b)*a ;d5 = d5(V1) + Ua ;060: scramble these 3*2... move.l d4,d0 sub.l d1,d0 ;d0=a (pixel.l) move.l d3,d2 sub.l d1,d2 ;d2=b (pixel.l) move.l d6,d7 sub.l d5,d7 ;d7.l=Ub<<16 (-+) divs.l d2,d7 ;Ub/b divs first because <<16 muls.l d0,d7 ;Ub/b*a add.l d7,d5 ;V1 Clipped ;d1= Y1=ClipY1 move.l d4,d1 .noclip_up ; +-------------------------------------+ ; / Clip Down / ;+-------------------------------------+ move.l src_ClipY2(a0),d4 cmp.l d4,d1 bge .end ;if out down, exit cmp.l d3,d4 bge .noclip_down move.l d3,d0 sub.l d4,d0 ;d0=a move.l d3,d2 sub.l d1,d2 ;d2=b move.l d6,d7 sub.l d5,d7 ;Ub divs.l d2,d7 muls.l d0,d7 ;a sub.l d7,d6 ;V2-a ... V2 Clipped ;d3=ClipY2 move.l d4,d3 .noclip_down ; +-----------------------------------------------------+ ; / Set Screen Pointer to Y line & find vector / ;+-----------------------------------------------------+ sub.l d1,d3 ;d3=Height to render. sub.l d5,d6 ;(V2-V1)<<16 divs.l d3,d6 ;texture Height vector subq.l #1,d3 ;to use with dbf.w move.l src_ChunkyScreen(a0),a3 move.l src_BytesModulo(a0),d0 mulu.l d0,d1 add.l d1,a3 ;a3 point the line to render. ;d1 is freed. ; +---------------------------------------------+ ; / Prepare Width vectors / ;+---------------------------------------------+ move.l a4,a6 move.l a5,d1 move.l d5,a4 move.l d6,a5 ; Here: ; d0: - ; d1: X2 ; d2: - ; d3: Y lenght to render. ; d4: -Clip ; d5: -U1 ; d6: -U2 ; d7: - ; a0: RC ; a1: TXTC ; a2: Kept for table ; a3: Chunky ptr ; a4: V Start <<16 ; a5: V Vector <<16 ; a6: X1 ; +-------------------------------------+ ; / Swap if order X is not right / ;+-------------------------------------+ ;d0 X1 ;d1 X2 move.l ttc_U1(a1),d5 ;U1 move.l ttc_U2(a1),d6 ;U2 cmp.l d1,a6 beq .end ; exit if 0 lines blt .noswapX ; if X1>X2 swap values move.l a6,d7 move.l d1,a6 move.l d7,d1 move.l d5,d7 move.l d6,d5 move.l d7,d6 sub.l #65536,d5 ;last pixel ->first is out (sub logic) sub.l #65536,d6 .noswapX ; +-------------------------------------+ ; / Clip Left / ;+-------------------------------------+ move.l src_ClipX1(a0),d4 cmp.l d4,d1 ble .end ;if out up, exit cmp.l a6,d4 ; have to be clipped or not ? ble .noclip_left ; >0 had to be clipped ;d5= V1 = ... ; a=(d4-a6) (>0) ; b=(d1-a6) (>0) ;Ub=(d6-d5) ;Ua=(Ub/b)*a ;d5 = d5(U1) + Ua ;060: scramble these 3*2... move.l d4,d0 sub.l a6,d0 ;d0=a (pixel.l) move.l d1,d2 sub.l a6,d2 ;d2=b (pixel.l) move.l d6,d7 sub.l d5,d7 ;d7.l=Ub<<16 (-+) divs.l d2,d7 ;Ub/b divs first because <<16 muls.l d0,d7 ;Ub/b*a add.l d7,d5 ;U1 Clipped ;a6= Y1=ClipY1 move.l d4,a6 .noclip_left ; +-------------------------------------+ ; / Clip Right / ;+-------------------------------------+ move.l src_ClipX2(a0),d4 cmp.l d4,a6 bge .end ;if out down, exit cmp.l d1,d4 bge .noclip_right move.l d1,d0 sub.l d4,d0 ;d0=a move.l d1,d2 sub.l a6,d2 ;d2=b move.l d6,d7 sub.l d5,d7 ;Ub divs.l d2,d7 muls.l d0,d7 ;a sub.l d7,d6 ;V2-a ... V2 Clipped ;d1=ClipY2 move.l d4,d1 .noclip_right ; +-----------------------------------------------------+ ; / Set Screen Pointer to X pixel & find vector / ;+-----------------------------------------------------+ add.l a6,a3 ;chunky start x,Y first pixel sub.l a6,d1 ;X2-X1 >0 d1=nb of pixel in width. sub.l d5,d6 ;U delta <<16 divs.l d1,d6 ;texture Width vector swap d5 ; addx trick for U vect swap d6 move.l src_BytesModulo(a0),d0 sub.l d1,d0 subq.l #1,d1 ;d1 original width length for loop - a6 freed move.l ttc_ChunkyTexture(a1),a0 ;no more need for RC. move.l ttc_BytesModulo(a1),a1 ; Here: ; d0: screen modulo - drawn width ; d1: X length to render(orig) ; d2: X length to render(dbf). ; d3: Y lenght to render. ; d4: - (things) ; d5: -U Start <<16 swaped(orig) ; d6: -U Vector <<16 swaped ; d7: -U Start <<16 swaped(scan) ; a0: Chunky Texture Start. ; a1: Texture modulo ; a2: Kept for table ; a3: Chunky ptr of line. ; a4: V Start <<16 ; a5: V Vector <<16 ; a6: Chunky Texture "at the line" ; +---------------------------------------------+ ; / Height Loop / ;+---------------------------------------------+ .loop_height ; find line on texture -> a6 move.l a0,a6 move.l a4,d4 ;V<<16 swap d4 ;V.w move.l a1,d7 ;texture modulo muls.w d7,d4 ;d4.l= V*txtmodulo add.l d4,a6 ; reset U scan move.l d5,d7 ;;;;;;;;;; add.l #0,d7 ;set "x" to 0. was optimlized by phxass. andi #$00f,ccr ; reset width loop. move.w d1,d2 ; +---------------------------------------------+ ; / Width Loop / ;+---------------------------------------------+ .loop_width move.b (a6,d7.w),d4 beq.b .noprint move.b d4,(a3) .noprint addx.l d6,d7 ;U vector addq.l #1,a3 ;miraculously doesnt reset "x". dbf.w d2,.loop_width ; +---------------------------------------------+ ; / End Width Loop / ;+---------------------------------------------+ add.l d0,a3 ; + rest of lines ;+ V vector add.l a5,a4 dbf.w d3,.loop_height ; +---------------------------------------------+ ; / End of Height Loop / ;+---------------------------------------------+ .end: movem.l (sp)+,d0-d7/a0-a6 rts ; /+===========================================================+/ ; // // ; // End // ; // // ;/+===========================================================+/